Among the advantages contemplated by the patentee of this railway, may be mentioned that of enabling the engineer, in most cases, to construct a railway on that plane which is most effectual, and where the shape of the country would occasion too great an expenditure on former plans - that of being maintained in a perfectly straight line, and in the facility with which it may always be adjusted; in being unencumbered with extraneous substances lying upon it; in receiving no interruption from snow, as the little that may lodge on the rail is cleared off by merely fixing a brush before the first carriage in the train; in the facility with which the loads may be transferred from the railway on to the carriages, by merely unhooking the receptacles, without displacing the goods, or from other carriages to the railway, by the reverse operation; in the preservation of the articles conveyed from being fractured, owing to the more uniform gliding motion of the carriages; in occupying less land than any other railway; in requiring no levelling or road-making; in adapting itself to all situations, as it may be constructed on the side of any public road, on the waste and irregular margins, on the beach or shingles of the sea-shore, - indeed, where no other road can be made; in the original cost being much less, and the impediments and great expense occasioned by repairs in the ordinary mode, being in this method almost avoided.
A. line of railway on this principle was erected, in 1825, at Cheshunt, in Hertfordshire, chiefly for conveying bricks from that town, across the marshes, for shipment in the river Lea. The posts which support the rails are about ten feet apart, and vary in their height from two to five feet, according to the undulations of the surface, and so as to preserve a continuous horizontal line to the rail. The posts were made of sound pieces of old oak, ship timber, and in the slots or clefts at the upper ends of the posts, are fixed deal planks twelve inches by three, set in edgeways, and covering with a thin bar of iron, about four inches wide, flat on its under side, and very slightly rounded on its upper side; the true plane of the rail being regulated or preserved by the action of counter-wedges between the bottom of the mortices, and that of the planks. By this rail, on the level, one horse seemed to be capable of drawing at the usual pace about fourteen tons, including the carriages.
The next invention in the order of time that presents itself to our notice, is one possessing considerable originality; and though it has not been carried into effect, it contains some ingenious suggestions, that have formed the groundwork of subsequent inventions. It is the subject of a patent granted to William Francis Snowden, of Oxford-street, London, on the 18th of December, 1824, for a "new invented wheel-way and its carriages for the conveyance of passengers, merchandise, and other things, along roads, rails, and other ways, either on a level or inclined plane."
The specification describes the invention under two distinct heads; the first, which is the most practical of the two, is explained as consisting of a hollow trunk with a platform of iron on the top for waggons or other carriages to roll upon; inside the trunk is placed a machine, called by the patentee a mechanical horse, to which is connected a toothed wheel, that is made to revolve in a horizontal plane, and to take into the teeth of a horizontal straight rack fixed on one side of the hollow trunk. The vertical axis of the horizontal toothed wheel passes through a longitudinal opening in the wheel-way; above which it is connected to a locomotive steam-engine, and is actuated thereby; through the medium of bevil gear the motion thus communicated to the latter by the engines is applied by the vertical axis to the horizontal wheel of the mechanical horse, inside the hollow trunk; and as the horizontal wheel is geared into the toothed rack, which is fixed on one side of the trunk, the mechanical horse of necessity moves forward with the same velocity as the horizontal wheel is made to revolve by the power of the engine.
This will be understood upon reference to the annexed figure, which affords a longitudinal section of the mechanical horse, and the hollow trunk or wheel-way. a is a vibrating cylinder, and b the boiler of a locomotive engine, by which the bevil gear e d is actuated, and through the medium of the vertical axis e, the horizontal toothed wheelfwhich takes into a toothed rack g; the mechanical horse h is made to advance in its course, and to take with it the engine and the train of waggons that may be in connexion. ww is the wheel-way, and t t the hollow trunk. As the top of the wheel-way is supposed to be flat, and the carriages without lateral flanges to their tires, it is proposed to guide the carriages by means of tongues like that at i, which enters the longitudinal apeture, and which may be provided with an antifriction roller to prevent lateral rubbing. The inventor proposes to adopt a similar arrangement to the foregoing for the towing of barges, by erecting his patent wheel-ways by the sides or banks of canals and rivers.
In the preceding pages are given some plans for the employment of toothed racks to railways, to enable a carriage, provided with a toothed wheel, taking into the teeth of the rack, to obtain sufficient resistance to ascend steep inclined planes: but the former were subject to the disadvantage of a strain or twist, the rack in them being placed on one side of the way. To obviate this defect appears to have been the object of Mr. Josiah Easton, who took out a patent, dated the 13th October, 1825, for "certain improvements in locomotive or steam carriages, and also in the manner of constructing the roads or ways for the same to travel on." The following brief description of this invention is given in the London Journal of Arts, Vol. XI.: - " These improvements consist, first, in forming a line of road, with a raised part along the middle, upon which a rack, or toothed bar of iron is placed; and secondly, in adapting a toothed wheel to the steam carriage, which shall take into the said rack, and being actuated by the rotatory power of the steam-engine, shall thereby cause the carriage to be impelled forward upon the line of railroad, and the trams or other waggons after it."